Novel approaches to render cancer cells more responsive to drug treatment must be developed. Based on the observation that the higher the growth fraction of the neoplasm, the steeper the drug dose response curve (an advantage), we propose to investigate the use of immunological enhancement to increase tumor cell proliferation and hence, increase its susceptibility to therapeutic agents such as whole body irradiation and chemotherapeutic agents. This approach has not been seriously considered nor has its use been critically evaluated in animal model systems. There are inherent risks associated with this approach. This proposal is designed to test the hypothesis that enhancement of tumor growth will make more cells vulnerable to cytolytic agents and consequently, a greater overall reduction in tumor burden may be achieved in the host provided the timing of enhancement and treatment can be precisely coordinated. This precision can be accomplished with the myeloma model where we can integrate staging, dose response, regrowth rates and drug resistance problems.